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Bipolar Flyback Diode/Snubber

Former Member

Hello,

 

I have an application where a motor runs both forwards and backwards. So the voltage polarity switches. Are there any configurations/products that anyone can recommend that would work as a flyback diode, for both the motor voltage polarities?

 

Best Regards,

Owen

  • 0

    Hi Owen,

    I assume you are using some sort of an H bridge. Some of the H bridges have built in protection. Check out your data sheet. If you are making the control out of discrete components you can put the flyback diodes across your transistors or MOSFETS. Just put the diodes into the circuit across the transistor and reversed bias.

    John

  • 0

    Hi Owen, Here are a couple examples of what I was saying. These schematics are from a great book called "Practical Electronics for Inventors" by Paul Scherz and Simon Monk.

     

    image

    You can see how the flyback diodes are inserted to protect the individual  driver transistors and are not put across the motor since, as you pointed out, the polarity of the motor is reversible.

     

    John